The present invention generally relates to avionics, and more particularly relates to weather radars, and even more particularly relates to methods and systems for suppressing ground clutter returns on avionics radars.
Over the years, the tasks and results expected of a commercial airline pilot have increased. The cockpit of a typical modern commercial jetliner is much more elaborate with electronic navigation, communication, and control equipment, than that of an early commercial passenger aircraft. This equipment, in general, has proven to be quite beneficial. A prime example is the weather radar, which is extremely helpful in guiding an aircraft comfortably through storms, etc. However, the weather radar displays have been plagued with a persistent problem of displaying unwanted and confusing ground clutter returns.
To address these problems, typically, a pilot will adjust the tilt angle of the weather radar antenna and will look to see if the display is different at different angles. The pilot would then mentally assimilate this information and reach a conclusion as to the true ambient conditions about the aircraft.
Other automated approaches have been attempted to suppress ground clutter, such as use of statistical analysis of the radar returns to assess the amount of variations in the returns. If the radar return variation characteristics were determined to more likely be resulting from ground targets, they were edited from the radar display.
While these attempts at ground clutter suppression have been used extensively in the past, they do have some drawbacks.
First of all, the pilot intervention efforts often would be quite burdensome to the pilot during times of severe weather. The pilot is most likely already extremely concerned with the ambient conditions, and deciphering the weather radar and manipulating it are extra burdens the pilot would much prefer did not exist. Additionally, these pilot tilt angle adjustments and their resulting analysis were tasks in which pilot error could occur.
Secondly, the use of statistical variation information to edit radar displays had a high rate of misidentification. Additionally, this approach was highly dependent upon the antenna beam to ground geometry.
Consequently, there exists a need for improved methods and systems for suppressing ground clutter for airborne weather radars in an efficient manner.
It is an object of the present invention to provide a system and method for suppressing ground clutter in an avionics weather radar in an efficient manner.
It is a feature of the present invention to utilize a plurality of geometrically and temporally closely spaced antenna scans.
It is another feature of the present invention to include a comparison of return profiles, including average radar power return levels as a function of beam geometry, with known or predicted profiles of average power of ground returns as a function of beam geometry.
It is an advantage of the present invention to achieve improved efficacy of ground clutter suppression systems and methods.
The present invention is an apparatus and method for improving the quality of ground clutter suppression in avionics weather radars, which is designed to satisfy the aforementioned needs, provide the previously stated objects, include the above-listed features, and achieve the already articulated advantages. The present invention is carried out in a xe2x80x9cmis-identification-lessxe2x80x9d manner in a sense that the mis-identification of weather as ground clutter has been greatly reduced. The present invention is also carried out in a xe2x80x9cpilot intervention-lessxe2x80x9d manner in the sense that pilot tilt angle adjustments and mental analysis of multiple returns to xe2x80x9cfilter outxe2x80x9d ground clutter has been reduced.
Accordingly, the present invention is a system and method including multiple closely spaced, in time and space, weather radar scans and a computer comparison of average power level of radar returns in relation to known variations of average power levels of ground returns as a function of beam geometry and orientation.